1. Field of the Invention
The present invention relates to an inserted cutting tool having a plurality of indexable cutting inserts releasably attached to a tool body through respective wedge blocks.
2. Prior Art
FIGS. 1 and 2 of the accompanying drawings show one conventional cutting tool 100 which comprises a tool body 102 having a central mounting bore 104 formed coaxial therewith and extending therethrough and a plurality of indexable cutting inserts 106 releasably attached to an outer periphery of the tool body 102 by means of respective clamp screws 108. Each clamp screw 108 has a disk-shaped head 108a and is threaded into the tool body 102 with the lower face of the head 108a held in abutting engagement with the front face of a respective one of the inserts 106 to thereby hold the insert 106 against movement.
In the cutting tool 100, however, a large space is required for the threading and unthreading of the clamp screw 108, and hence it has been practically possible to attach an increased number of the cutting inserts 106 to the body 102. Besides, there may be produced a gap between the front face of the insert 106 and the head 108a of the screw 108, and chips produced during the cutting operation may be jammed in the gap.
Another conventional inserted cutting tool 100a shown in FIG. 3 comprises a plurality of support members 110 fixedly secured to an outer periphery of a tool body 102a, a plurality of cutting inserts 106a each received in a respective one of the support members 110, and a plurality of wedge blocks 112 for holding the inserts 106a against the support members 110, respectively, each wedge block 112 being fixedly secured to the body 102a by a respective clamp screw 114 threaded thereinto. The clamp screw 114 is so disposed as to extend radially inwardly and axially rearwardly of the body 102a, whereby a prescribed wedge angle defined by the axis of the clamp screw 114 and the front face of the insert 106a is imparted to the wedge 112. With this construction, the clamp screw 114 is tightened to cause the wedge block 112 to wedge the insert 106a against the body 102a.
In the cutting tool 100a, however, a threaded hole 116 into which the clamp screw 114 is threaded has to be made shorter so as not to interfere with the central bore 104. As a result, a longer clamp screw cannot be employed, and hence the clamping force of the insert has been insufficient. Besides, insomuch as the threaded hole 116 extends axially rearwardly of the body 102a, the torsional rigidity of the body 102a has been unduly low.